The Ford Y-Block temperature sending location at the back of the engine typically reads 15°-20°F lower than what is seen at the thermostat.  Moving the sending unit to the front of the engine will have the factory temp gauge reading a much warmer temperature.  Relocating the sending unit is recommended when adding a non-stock temperature gauge, but the factory gauge will simply show a much hotter temperature when in reality nothing changed.  Converting these engines to an aftermarket fuel injection setup will require that the temperature reading come from the front of the engine so it can have access to the warmer engine temperature reading.

Lorena, Texas (South of Waco)

The sender location isn’t ideal, but those old gauges weren’t all that accurate to begin with. Since they’re the King Seeley’s you can’t just add a resistor. There is some adjustment, but it’s almost impossibly to do unless they’re on a bench, hooked to a battery, and you can make small changes and wait.

Blacktie has the best solution. A 2 or 3 gauge panel. Water, oil, and volts if you’d like.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Ted Eaton recommends relocating the temperature sender from the back of the driver-side head to the intake manifold. While he had my ECZ-B intake manifold, I asked Ted to drill & tap it for a sender. Looking at the engine from the front, the intake manifold was drilled and tapped into the coolant crossover, just to the left of the heater-control valve. This location, according to Ted, will provide a more accurate temperature reading than the location at the back of the head. 

There are adapters that are attached to the upper radiator hose that will accommodate a temperature sender, but that location, which is in front of the thermostat, can give a false reading, in the event that the thermostat fails to open. Although my car is not back on the road yet, I'm retaining the original 55 Tbird sender and gauge (sender in original location), putting an AutoMeter sender in the manifold, and using an AutoMeter gauge. If one were to fail, the other will still be functional. 

Is there a better location for the temp sender (1955 292 Tbird, 12 volt)?   I've had the gauge pegged VERY HARD to the right, physically it could not more any further right.   The car didn't boil over.  An IR temp gun top tank was at 210 degrees.  It ran OK, but I could feel a slight degradation to the idle from the under hood heat.

The gauge and sender in my car are from Casco.   They are a matched pair that operates at 12 volts.   I think the problem may be the location of the sender.

I would like to see something with a more useful scale.   I don't feel like I would have any clue if the radiator will boil over or not